1. Field of the Invention
The present invention relates to construction tools; and, in particular, the present invention relates to devices which enable precise angled cuts in roofing materials.
2. Description of Related Art
When building or replacing roofs on houses and similar buildings, sheets of roof decking are placed over structural members such as truss chords. The decking is typically standard-sized outdoor grade plywood. In many roof designs, end pieces are easily formed from the standard-sized decking by simply measuring and cutting the sheets to fit. However, in roofs such as hip roofs, each borderpiece formed to be placed proximate a hip rafter must be premeasured, then angularly cut to ensure a fit. This procedure is inefficient and time-consuming.
A rafter-measuring tape is disclosed in U.S. Pat. No. 3,289,305. The rafter-measuring tape includes a series of arced cutting marks. Graduations present on the slide surface cooperate with the cutting marks to enable rafters to be cut for various roof pitches. However, the rafter-measuring tape contains no guidance for forming angular borderpieces from standard-sized decking.
U.S. Pat. No. 4,462,166 discloses a device for measuring links and conforming angles. The device includes a telescoping measuring rafter gauge. The rafter gauge includes two telescoping members with locking devices. The device further includes two sliding pitch locating plates, each with a tightening device. The pitch locating plates fit flush against a center ridge board or hip rafter. Graduations are present along the telescoping inner member of the rafter gauge. Hinge means are provided on the telescoping outer rafter for attachment to the center ridge board. The device of U.S. Pat. No. 4,462,166 fails to disclose or suggest how it may be used to form borderpieces with angular edges.
U.S. Pat. No. 4,712,307 discloses a rafter angle measuring device. The device includes a body in the form of a generally U-shaped plate of metal with a horizontal base and spaced first and second vertical arms at opposite ends of the horizontal base. A third arm is pivotally connected to the plate proximate the end of the base bearing the first arm. The third arm extends beyond the second arm. The third arm receives and is releasably securable to one or both of the first and second arms in any position between the horizontal and vertical. The first arm has a generally triangular support portion secured to the base about half-way along the length thereof. The first arm defines a spaced pair of curved slots with angled hip rafter valve and common jack plumb cut indicia disposed along the perimeter of the slots. The support portion displays door sill and window sill indicia. At least one margin of each of the three arms and the base display linear indicia in fractions of an inch. The third arm has a bubble level in a cage. The bubble level is releasable from all major angles. The base is adapted to measure roof rafter angles and also serves as a U-square. The device of U.S. Pat. No. 4,712,307 also fails to suggest or disclose how one would form borderpieces with angular edges.
U.S. Pat. No. 4,916,822 discloses an angle- and distance-measuring instrument. The instrument provides two straight arms connected at one end for relative pivotal movement. A telescoping assembly has two elongated telescoping members, each member with a free end. The free end of one telescoping member is pivotally connected to one arm, and the free end of the other telescoping member is connected to the other arm. The telescoping members provide scales indicating the angular position between the two arms. The distance between the pivots of the free ends of the telescoping members and a correction for measurement along the ends of the arms establish distances from the corner being measured. The two arms can pivot 360.degree. relative to each other and permit the measurement of inside and outside corners. A straight edge is removably mounted on one of the arms when measuring outside corners. A level is provided to establish the position of one of the arms relative to a horizontal direction. This instrument would be impractical in defining a borderpiece with angular edges, as well.
U.S. Pat. No. 5,539,991 discloses an adjustable sheathing square. The adjustable sheathing square scribes cut lines on large, flat panels. The device has a straight, flat, rectangular bar which serves as a base member. An angularly-adjustable arm is pivotally connected at one end to the base member. The adjustable pivot arm also includes a straight, flat, rectangular bar with an arcuate extension where the pivot arm is connected to the base member. The arcuate extension extends through a slot in the base member and is marked in degrees to form a quarter-circle protractor integral with the pivot arm. The protractor defines an arcuate groove, which is parallel with the outer edge of the arcuate extension. An adjustable stop extends through the groove and through the base member. The arcuate extension is pivoted on a pin affixed at the end of the base member. Releasing the adjustable stop permits the pivot arm to be angled relative to the base member to the desired degree, as indicated on the protractor. While potentially useful in forming decking borderpieces, the angles must be premeasured before the device can be used. Thus, there is a need for a device which enables borderpieces to be formed without either premeasuring or predetermining angles or using tables or formulae.
Thus, while several devices can measure and delineate cuts to be made when rafters are formed, there are relatively few devices for forming borderpieces from standard-sized sheathing.